JP2007244103A - Composite material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite material that can be curved and deformed by giving a potential difference and that is operated by small electric power, whose deformation amount is large, whose response is quick, the degree of freedom of the shape of which is large, the control of the deformation of which is easy, and furthermore that has strength and durability required for practical use, and that is excellent in the aspect of economy. <P>SOLUTION: The composite material is obtained that causes an ion conduction membrane to be deformed, by joining conductive cloth (preferably having elasticity), which is made conductive by plating a metal on or injecting metal complex into the cloth as electrodes, on both sides of the ion conductive membrane (an ion exchange membrane or a membrane impregnated with an ionic liquid) comprising a fluorine system resin and the like, and by giving the potential difference. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a composite material in which electrodes are bonded to both surfaces of an ion conductive membrane, and can be curved and deformed using a potential difference. More specifically, the present invention is formed by bonding a conductive fabric as an electrode to both surfaces of an ion conductive membrane, and has excellent deformation force and quick response, a large degree of freedom in shape, and further necessary for practical use. The present invention relates to a composite material that has excellent strength and durability characteristics and is also economically superior.

  A technology has already been proposed for providing electrodes on both surfaces of an ion conductive membrane and causing the ion conductive membrane to bend and deform by applying a potential difference to the electrodes, and electrodes are provided on both surfaces of such an ion conductive membrane. Since the composite material has a simple structure and can be easily miniaturized, and operates with low power, it is used as an actuator element.

  For example, Patent Document 1 discloses that a noble metal coating formed on both surfaces of an ion exchange membrane by using a plating technique or the like is used as an electrode, and a slight voltage of several volts is applied to move the electrolyte in the membrane. There has been proposed a method of deforming the above. In addition, a composite material obtained by chemically plating gold as an electrode on an ion exchange resin has been proposed as an actuator element by Emex (see Patent Documents 2 and 3).

JP 7-4075 JP2004-197215 JP-A-2005-187926

  However, in the conventional technique in which the electrode metal film is formed on both surfaces of the ion conductive film by a technique such as plating, a metal film lacking flexibility and flexibility is provided on both surfaces of the ion conductive film. There is a drawback that the bending and deformation of the film tend to be inhibited, and it is difficult to obtain sufficient deformation force and quick response.

  That is, since the composite material of the ion conductive film and the electrode metal film is thick, when the composite material is curved, a difference in length occurs between the inner surface and the outer surface of the curve. In other words, it is necessary that the inner film shrinks or the outer film grows. However, the ion conductive membrane has the elasticity, flexibility and flexibility necessary for deformation when wet, whereas the metal membrane is poor in elasticity and flexibility. In some cases, it becomes a resistance to weaken the deformation force and slow down the deformation speed.

  In particular, as the metal film thickness of the electrode and the ion conduction film thickness increase, this tendency becomes more prominent, so it is difficult to increase the deformation force by thickening the ion conduction film, and as a result cannot follow a large deformation, There were problems such as weak deformation force and slow reaction.

  In addition, there were problems with practicality and durability. In the above-described conventional technology, the electrode metal film provided on both surfaces of the ion conductive film is bent by applying a potential difference, and returns to the original state when the application is canceled, and uses the property of bending to the opposite surface when the reverse potential is applied. The purpose can be achieved by appropriately selecting and repeating these changes according to the purpose.

  However, in the prior art, a metal thin film having poor bending durability tends to be broken by repeated large deformation and bending. This tendency becomes more prominent because the metal film provided as the electrode is required to be formed as thin as possible in order not to inhibit the bending and deformation of the ion conductive film.

  In addition, if the ion conductive film is thickened to increase the deformation force, the difference in dimension between the inner surface and the outer surface increases when bending, and the force applied to the metal film as an electrode increases, making it more difficult to bend and deform. It becomes easy to break. If the metal film of the electrode is thickened to prevent breakage, it becomes difficult to bend and deform, and the purpose cannot be achieved.

  Furthermore, in the configuration in which metal thin films as electrodes are provided on both surfaces of the ion conductive film, it is difficult to obtain characteristics as a composite material necessary for practical use, such as tensile strength and wear strength enough to withstand practical use. That is, it was not possible to obtain performance sufficient to withstand the stress applied to the composite material in practical use such as tension, bending, shearing, and abrasion. That is, for example, many metal films used for conventional electrodes have poor stretchability, and when the composite material is stretched by about 10%, the metal film is destroyed and cannot be used as an electrode. This tendency is particularly strong in electrode metal films obtained by plating techniques.

  Thus, in the technology that has been proposed conventionally, in order to obtain sufficient bending and deformation when a voltage is applied, it is necessary to limit the material, thickness, etc. of the electrode, ion conductive membrane, tension, Resistance to stresses such as bending, shearing, and abrasion could not be sufficiently improved.

In addition, there is a limitation on the shape of the composite material in order to obtain the desired curvature and deformation. For example, in order to deform as shown in FIG. 2 by applying a potential difference to both surfaces of the ion conductive membrane to cause a swelling difference on both sides of the membrane to bend by moving the electrolyte in the membrane, a rectangular shape, preferably It is necessary to make it a rectangle with a large difference between the long and short sides. If it is applied to both sides of a square, deformation due to swelling occurs in the four corners of the square, and deformation as shown in FIG. 2 cannot be expected. Further, the bending in the case of a rectangle occurs in the long side direction and cannot occur in the short side direction. As described above, since the shape of the composite material is limited in the prior art, usage and usage are limited, and it is not easy to devise such as widening the width and increasing the bending force.
Moreover, since it takes man-hours and time to form electrodes on both surfaces of the ion conductive film by a technique such as plating, improvement in cost has been a problem.

  The present invention solves these problems, a method for bending and deforming a conductive film by applying a potential difference, and a composite material suitable for the method, which operates with a small electric power, has a large amount of deformation, has a fast response, and has a shape. An object of the present invention is to provide a product that has a high degree of freedom, can easily control deformation, has practically necessary strength and durability characteristics, and is excellent in terms of economy.

  As a result of intensive investigations to achieve the above object, the present inventors have found that the above problem can be solved by laminating a conductive fabric on both sides of the ion conductive film instead of forming a metal film as an electrode by a technique such as plating. The present invention has been found.

That is, this invention provides the composite material shown to the following (1)-(8).
(1) A composite material comprising an ion conductive membrane and electrodes joined to both surfaces of the ion conductive membrane, and causing the ion conductive membrane to be deformed by applying a potential difference to the electrode, wherein the electrode is composed of a conductive cloth. A composite material characterized by being made.
(2) The composite material according to (1), wherein the ion conductive membrane is an ion exchange membrane or a membrane impregnated with an ionic liquid.

(3) The composite material according to (2), wherein the ion-exchange membrane or the membrane impregnated with an ionic liquid is made of a fluororesin polymer.
(4) The composite material according to any one of (1) to (3), wherein the conductive fabric is a composite of the fabric and metal by a plating method or metal complex injection.

(5) The composite according to any one of (1) to (4), wherein an electrode bonded to at least one surface of the ion conductive film is formed of a conductive cloth having elasticity. material.
(6) The composite material according to any one of (1) to (5), wherein the conductive fabric has a difference in stretchability between two orthogonal axes.
(7) The composite material according to (6), wherein the difference in stretchability is 2% or more.
(8) The conductive fabric is bonded to the ion conductive film so as to have elasticity in a direction in which the ion conductive film deforms when a potential difference is applied to the electrode. (5) The composite material according to any one of to (7).

  The composite material of the present invention uses a conductive fabric that is superior in flexibility, stretchability, and flexibility as compared with a metal film formed by plating or the like as an electrode to be bonded to both surfaces of an ion conductive film. The amount of deformation at the time is large, the response is fast, and the degree of freedom in shape is also large. Furthermore, the deformation can be easily controlled, and it has strength and durability characteristics necessary for practical use, and is excellent in terms of economy.

  Hereinafter, the composite material of the present invention will be described in detail with reference to the drawings. The composite material of the present invention comprises an ion conductive film and electrodes bonded to both surfaces of the ion conductive film, and causes the ion conductive film to be deformed by applying a potential difference to the electrodes. FIG. 1 is a diagram showing an example of the composite material of the present invention. As shown in FIG. 1, the composite material of the present invention includes an ion conductive film 1 and electrodes 2 and 2 ′ in contact with both surfaces of the ion conductive film 1.

(1) Ion Conductive Membrane In the present invention, the functions required of an ion conductive membrane are the presence of an ionic substance that can be moved by the application of a potential, and the degree of swelling changing as the ionic substance moves. .

  Therefore, there is no particular limitation as long as it is a film made of a material having such a function. Specifically, as an ion conductive film having such a function, a cation exchange membrane, an anion exchange membrane, and an ionic liquid are used. And the like can be mentioned.

Although it does not specifically limit as a cation exchange membrane, For example, a sulfone group, a carboxylic acid group, as an anionic functional group to well-known resin, such as polyethylene, polystyrene, a polyimide, polyarylenes (aromatic polymer), A perfluorocarboxylic acid resin, a perfluorosulfonic acid resin in which a phosphoric acid group is introduced, or a fluororesin-based polymer such as tetrafluoroethylene or polyvinylidene fluoride, in which the above anionic functional group is introduced, Perfluorophosphoric acid resin or the like can be used. Such a cation exchange membrane may be commercially available, and for example, a perfluorosulfonic acid / PTFE copolymer (trade name “Nafion ^™ ”, manufactured by DuPont) membrane may be used.

  The anion exchange membrane is not particularly limited, but for example, a known functional resin such as polyethylene, polystyrene, polyimide, polyarylene (aromatic polymer), and a cationic functional group such as ammonium, sulfonium, phosphonium, oxonium. A group into which a cationic functional group is introduced into a skeleton such as tetrafluoroethylene or polyvinylidene fluoride, which is a fluororesin-based polymer, can be used.

  Further, the membrane impregnated with the ionic liquid is not particularly limited. For example, polyethylene (polystyrene, polystyrene, polyimide, polyarylenes, tetrafluoroethylene, polyvinylidene fluoride, etc. used for the ion exchange membrane (functional It is also possible to use a film formed by impregnating an ionic liquid into the same polymer as that before introduction of the group.

  The ionic liquid is not particularly limited. For example, an organic compound salt that is liquid at room temperature, specifically known compound salts such as imidazolium salt derivatives, pyridinium salt derivatives, phosphonium salt derivatives, tetraalkylammonium salt derivatives, etc. Can be used.

  The imidazolium salt derivative is not particularly limited, but examples thereof include 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium tetrafluoro. Borate, 1-ethyl-3-methylimidazolium iodide, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium Bromide, 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-n-butyl-3-methylimidazolium tetrafluoroborate, 1-n-butyl-3-methylimidazolium hexa Fluorophosphate, 1-n-butyl-3-methyl Dazoriumu chloride, 1-ethyl-3-methylimidazolium bromide, and the like.

  The thickness of the ion conductive film is not particularly limited, but is preferably about 5 to 5,000 μm. When the film thickness is small (thin), the film is easily deformed, but the deformation power (force to be deformed) by applying a constant voltage is small. Conversely, when the film thickness is large (thick), it is difficult to deform itself, but the power by applying a constant voltage increases. Since the film thickness and the required power differ depending on the application, it is preferable to select appropriately according to the application.

(2) Conductive fabric The composite material of the present invention is characterized by using a conductive fabric as the electrode. That is, a conductive cloth obtained by metallizing a fiber cloth is used for the electrodes 2 and 2 ′ bonded to both surfaces of the ion conductive film.

  The fiber fabric may be any of a woven fabric, a knitted fabric, and a non-woven fabric, and can be appropriately selected from these according to the shape and purpose of the composite material. Although there is no restriction | limiting in particular as a material of the fiber which comprises a fabric, Synthetic fibers, such as a polyester fiber, a polyamide fiber, a polyacryl fiber, or a polyolefin fiber, which are excellent in terms of strength and durability, are preferably used.

  The conductive fabric is a composite of a fabric and a metal. The conductive fabric is made conductive by plating, or a metal or metal complex is injected into the fiber using a supercritical carbon dioxide fluid. Although it is manufactured, the former is more advantageous in terms of cost. In addition to this, it may be a fabric made by a method such as weaving or knitting a fiber previously imparted with conductivity by plating or the like, or a fibrous material imparted with conductivity made a non-woven fabric by a normal method. Good. The manufacturing method of the conductive fabric used in the present invention is not limited to this, and any method may be used as long as a conductive fabric is obtained.

  According to the method of making a fabric conductive by plating, a metal coating layer can be formed on the fiber surface to uniformly metalize the fabric. As the specific method, a conventionally known electroless plating method and electroplating method are preferable. The plating bath includes a metal salt, a reducing agent, a buffering agent, a pH adjusting agent, and the like.

Any metal can be used as long as it has conductivity, but noble metals such as gold, platinum, iridium, palladium, ruthenium, etc. are used in terms of durability. Then, copper, nickel, tin, silver, etc. are more preferable.
Although the thickness of the metal coating layer formed is not specifically limited, It is preferable to exist in the range of 0.1-10 micrometers. If the film is smaller than 0.1 μm, sufficient surface conductivity cannot be obtained, and if it is larger than 10 μm, the flexibility of the fabric may be impaired. The metal film does not need to be of one type, and after plating a metal on the fabric, it may be multilayered by another metal using electroplating or electroless plating.

  Among the conductive methods, metal complexes used in the method of injecting metal complexes include bis (acetylacetonato) palladium (II), bis (acetylacetonato) nickel (II), and bis (acetylacetonato) copper. (II), bis (η-cyclopentadienyl) nickel (II), dichloro (1,5-cyclooctadiene) palladium (II), 1,5-cyclooctadiene) dimethylplatinum (II), bis (benzo Nitrile) dichloropalladium (II), bis (hexafluoroacetylacetonato) palladium (II), bis (hexafluoroacetylacetonato) nickel (II), bis (hexafluoroacetylacetonato) copper (II), etc. .

  The conductivity of the conductive fabric used in the present invention is not particularly limited, but as the preferable conductivity, one having a surface resistance value of 1.0 Ω / □ or less can be used.

  In order for a composite material mainly composed of an ion conductive membrane to bend, electrodes bonded to both surfaces of the ion conductive membrane need to expand and contract in order to eliminate the difference in dimension between the inside and outside of the bendable composite material. Therefore, it is preferable to join an electrode made of a conductive fabric having elasticity.

  The conductive fabric rich in stretchability may be bonded to at least one surface of the membrane, and may be only one side or both sides of the membrane. The direction in which stretchability is exhibited is not particularly limited, and may be a fabric that exhibits uniform stretchability in all directions, or may exhibit good stretchability in a specific direction. As a specific measure of stretchability, the average stretch degree is preferably 2% or more, more preferably 5% or more, but is not limited thereto. In addition, the average expansion / contraction degree here is the maximum expansion / contraction degree under conditions where the deterioration of conductivity is 10% or less.

  When using a conductive fabric exhibiting good stretchability in a specific direction, bonding is performed so that the fabric exhibits good stretchability in the direction in which the ion conductive film deforms or a desired deformation direction when a potential difference is applied. It is good. That is, in consideration of the stretchability of the conductive fabric, it is preferable to adjust the joining direction of the conductive fabric so that the conductive fabric can be stretched following the deformation of the composite material.

  Furthermore, it is preferable that the conductive fabric has a difference in stretchability between two orthogonal axes. More preferably, the difference in stretchability is 2% or more, and most preferably 5% or more. By using such a conductive fabric having good stretchability, it is possible to obtain a composite material in which desired deformation can be easily obtained regardless of the shape of the composite material.

  The two orthogonal axes here are arbitrarily set such that the difference in stretchability is maximized on the surface of the conductive fabric. Therefore, the difference in stretchability referred to here is the difference in stretchability between the two orthogonal axes selected as such, and the maximum value of the difference in stretchability between any two orthogonal axes on the fabric. .

  By using such a conductive fabric having good stretchability in a specific direction, the conventional technology can only deform the long side direction of the composite material, and can control the deformation of the short side direction and the square material. We solved the problem that there was not, and made it possible to control the deformation regardless of the shape.

  The thickness of the conductive fabric is not particularly limited and can be appropriately selected according to the characteristics and applications required of the composite material, but is preferably 5 to 5,000 μm. Within this range, a good balance between the force to be deformed and the ease of deformation can be maintained.

  In the present invention, the use of a conductive fabric that is superior in flexibility, stretchability, and flexibility as an electrode as compared with a metal thin film prevents the ion conductive membrane from being bent or deformed. The fabric used for the conductive fabric is appropriately selected depending on its use and purpose. For example, when the displacement is large and importance is attached to the stretchability of the electrode, a circular knitting rich in stretchability is more suitable, and when tensile strength is required, a woven fabric is more suitable. In any case, by using a conductive fabric that is excellent in flexibility, stretchability, flexibility, and abrasion resistance as an electrode, it is possible to impart a practical characteristic to the intended composite material.

  In addition, the conductive fabric of the present invention can be industrially produced in advance by a known method, which is advantageous in terms of cost compared to a conventional method of plating a metal on a conductive film.

(3) Composite Material In the composite material of the present invention, in order to give a potential difference to the electrode to cause bending and deformation, the ion conductive membrane needs to be in a water-containing state when it is an ion exchange membrane. Here, the water-containing state means that the composite material operates in water or in a high humidity atmosphere. In water, ions contained in the surrounding water may affect the operation, but it can also operate in liquids containing various solutes.

  If the electrodes 2 and 2 'are connected to an arbitrary waveform generating power source (DC power source or AC power source) via lead wires, the composite material of FIG. 1 is bent as shown in FIG. Although the operating mechanism or principle is not clear, when an ion exchange membrane is used, a potential difference is applied to the front and back of the membrane, so that positive ions 3 in the ion exchange membrane 1 are moved to the cathode 2 'side as shown in FIG. It is presumed that there is a difference in water content and osmotic pressure between the anode side and the cathode side because water molecules move in the membrane accompanying the movement of ions. Therefore, it swells when the moisture content increases, and contracts when the moisture content decreases, so it is considered that the membrane bends if there is a difference in moisture content or ion concentration between the front and back of the membrane.

  However, even if there is a difference in ion distribution, if the movement of ions stops in that state, it is estimated that the moisture distribution gradually approaches the original uniform state due to diffusion of water from the outside of the membrane. In other words, if the current in the membrane decreases even when a constant voltage is applied, the distribution of water content that has once occurred is gradually averaged, so that the curve is considered to return to its original state. Thus, the state of bending can be controlled by the value of the voltage, and the bending can be repeated.

When the cation exchange membrane is used in pure water, the ions that move are H ⁺ ions, and when used in saline, it is thought to be Na ^+. Move to the cathode side. Considering in this way, the moisture content of the membrane on the cathode side increases and the moisture content on the anode side decreases, so the cathode side extends and the anode side shrinks, so the membrane curves to the anode side.

  The ions in the ion conductive membrane are not particularly limited, but in the case of a cationic membrane, other ions such as alkali metal ions such as lithium ions, sodium ions, potassium ions, beryllium ions, magnesium ions are used instead of protons. Organic or inorganic cations such as alkaline earth metal ions such as calcium ions, ammonium ions, pyridinium ions, sulfonium ions, phosphonium ions, and oxonium ions can be used. In the case of an anionic membrane, sulfonic acids, carboxylic acids, phosphoric acids and the like can be used. When protons in the cationic membrane are exchanged with, for example, lithium ions, a composite material having a large curvature and bending deformation can be obtained.

  When an ion conductive membrane in which an ionic liquid is impregnated with a fluorine-based or aromatic polymer membrane is used, an ionic liquid in the membrane moves toward the electrode by applying a potential difference to the front and back of the membrane, thereby It is estimated that the same phenomenon as that of the exchange membrane occurs. In the case of an ionic liquid, it is not water that moves, but ions of the ionic liquid that move, so that even under a low temperature, the curved movement can be performed without being affected by the temperature as in the case of water. In addition, the ionic liquid has an advantage that it is less likely to evaporate than water, and stable bending is possible even in an environment where the outside air is dry.

  In addition, the conventionally proposed technique has a drawback in that the shape is limited in principle. That is, if the shape of the element is a rectangle, the element is bent in the long side direction and is not bent in the short side direction. Further, when a potential difference is applied in a square shape, only the corners at four corners are deformed. In other words, in the case of the conventional technique, in order to obtain the deformation and curvature as shown in FIG. 2, it is necessary to increase the difference between the rectangle, particularly the long side and the short side.

  However, the present invention can also solve this problem. The fiber fabric can obtain a wide variety of stretch properties due to the fabric structure such as yarn processing, woven fabric, and knitted fabric. It is possible to easily make a material having elasticity in only one direction of warp and weft and a material having elasticity in all directions. By making this fiber fabric conductive, a conductive fabric having the same stretchability can be easily obtained.

  In the present invention, by using such a conductive fabric for an electrode, the direction of bending and deformation can be freely designed. That is, in the past, it was not possible to create a composite material that curved in the direction of a square or short side, but by using a conductive fabric that has a difference in stretchability in the warp and weft directions, it would be easier to stretch. Can bend and deform. This makes it possible to design the direction of bending and deformation by utilizing the directionality of the stretchability of the electrode regardless of the shape of the electrode. This means that there is no restriction on the shape of the composite material. As a result, for example, the force can be increased by curving in the direction of the short side, or the shape requirement according to the application can be easily met. Is possible.

(4) Manufacturing method of composite material As shown in FIG. 3, the composite material of this invention can be manufactured by laminating | stacking the ion conductive film 1 and the conductive fabrics 2 and 2 '. The method for laminating is not particularly limited, and a method used in a usual method for producing a laminated film can be appropriately employed. Preferably, the ion conductive membrane is sandwiched between two conductive fabrics, and the ion conductive membrane is used. It can be manufactured by making a sandwich shape in which a conductive fabric is in contact with both sides of the sheet, and then applying pressure (about 0.0001 to 10 tons) to this sandwich from one side or both sides. At this time, hot pressing can be performed by applying a pressure (preferably about 40 to 300 ° C.) that does not dissolve the ion conductive membrane while applying pressure.

  In addition, when sandwiched, the both sides can be covered with a polymer film or a metal plate, and then hot pressing or the like can be performed from above. As the polymer film used as the cover or supporter (4 in FIG. 3), a general-purpose polymer film such as a polyester film such as PET (polyethylene terephthalate) can be used. Moreover, as a metal plate, an aluminum plate, a copper plate, a stainless plate, etc. can be used. When using a metal plate, a recess for setting the conductive fabric and the ion conductive film is formed on the surface. After the ion conductive membrane and the conductive fabric are joined, these covers or supporters are removed.

The conductive fabric is preferably impregnated with a solution in which a polymer having high adhesion to the ion conductive membrane is dissolved before being brought into contact with the ion conductive membrane. For example, in the case of a fluorine-based polymer, it is preferable to impregnate a solution in which a polymer such as “Nafion ^™ ” having a fluorine skeleton is dissolved. The soaked polymer serves as a binder, and good bonding between the ion conductive membrane and the conductive fabric can be maintained.

(5) Use of composite material The composite material of the present invention has an excellent rapid response to deformation with a high deformation rate by applying an arbitrary waveform voltage (DC voltage or AC voltage) of about 0.1 to 10 V between the electrodes. And can be achieved with deformation controllability. Moreover, the degree of freedom in shape is high, and the strength and durability are also excellent. Therefore, the composite material of the present invention can be applied as an actuator element to various uses such as medical equipment, industrial robots, and micromachines. For example, it can be used as an artificial muscle for a micro robot operating in water, and can also be applied to the power of a medical instrument used in a living body.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited only to these examples. In addition, the evaluation method of each physical property in the following examples is as follows.

<Processing cost>
Considering the man-hours and time required to create the composite material, the evaluation was made according to the following criteria.
○: Can be manufactured within 1 hour by bonding conductive fabric ×: Electrodes are formed on both sides of the film by plating. It takes 20 hours or more to form a 5 μm film.

<Deformability>
The displacement in the long side direction when a DC voltage of 3 V was applied to the evaluation sample (3 × 15 mm) was measured and evaluated according to the following criteria.
○: Displacement 5 mm or more Δ; Displacement 2 mm or more to less than 5 mm ×; Displacement less than 2 mm

<Strength (tensile strength)>
The evaluation sample of the example was cut to prepare a composite material of 10 mm × 10 mm, and the electrode destruction situation when a load of 1 kg was applied to this was evaluated by the following criteria by measuring the conductivity deterioration, and judged. did. Here, the conductivity degradation was evaluated as the conductivity degradation by measuring the surface resistance value (conductivity) of the composite material with and without a load, and the rate of change (surface resistance value change rate). In addition, the surface resistance value measured the electroconductivity in clip equilibrium electrode width 10cm and distance 10cm between electrodes using the resistance value measuring device milliohm high tester 3220 by Hioki Electric Co., Ltd. (clip method).
○: Less than 10% conductivity deterioration ×: More than 10% conductivity deterioration

<Strength (flexibility)>
For the evaluation sample (3 × 15 mm), the state of electrode breakage after repeating 180 ° bending 10 times was determined by measuring the conductivity and using the following criteria.
○: Less than 10% conductivity deterioration ×: More than 10% conductivity deterioration

<Surface resistance value>
As for the surface resistance value of the conductive fabric, conductivity was measured at a clip balanced electrode width of 10 cm and an inter-electrode distance of 10 cm using a resistance value measuring device milliohm high tester 3220 manufactured by Hioki Electric Co., Ltd. (clip method).

<Elasticity>
Cut the conductive fabric into 10 mm x 10 mm, measure the conductivity using the measurement method of the surface resistance value, measure the elongation by applying a load, increase the load, and the conductivity deterioration is 10% The elongation at that time was taken as the degree of stretch.

[Example 1]
As an ion conductive membrane, a perfluorosulfonic acid / PTFE copolymer (trade name “Nafion ^™ ”, manufactured by DuPont) having a thickness of about 200 microns was prepared (proton type) (2 cm × 5 cm). This Nafion membrane was heated in 500 mL of 5M nitric acid aqueous solution at 80 ° C. to 100 ° C. for 30 minutes and washed thoroughly with ion-exchanged water. Next, it was immersed in 500 mL of ion exchange water and boiled for about 30 minutes. In this way, a Nafion membrane used for the composite material was obtained.

On the other hand, about 60 g / m ² of polyester fabric (taffeta) is gold-plated by a known method to obtain a conductive fabric having a surface resistance of 0.1 Ω / □ (thickness: 90 μm, average stretch; %, 10% in the bias direction, and a difference in stretchability in the bias direction; about 0%). Two pieces of this conductive fabric (2 cm × 5 cm) are cut out in the bias direction, immersed in a lower alcohol solution in which Nafion is dissolved, and then the previously washed Nafion membrane is quickly sandwiched between the two nonwoven fabrics. It is.

  The obtained sandwich is quickly covered with two polyester (PET) films of about 6 cm × 10 cm from both sides, and set in a hot press set at a temperature of 90 ° C. Apply a pressure of about 0.5 tons at the start. It was taken out after 30 minutes and cut to 3 mm × 15 mm to obtain a composite material in which an ion conductive membrane and a conductive fabric (nonwoven fabric) were laminated. It was confirmed that the obtained composite material (composite film) non-woven fabric and Nafion film were in close contact, and the film was deformed by a DC voltage of about 1 to 5V.

  The composite membrane was immersed in a lithium hydroxide solution of about 0.2 M for about 1 hour, and the proton inside was exchanged for lithium ions. After rinsing with ion-exchanged water and lightly wiping off the water on the surface, it was confirmed that it was deformed by a DC voltage of about 1 to 5V. Moreover, as a result of evaluating the tensile strength and the bending resistance of the composite material exchanged with the lithium ion, both were excellent. The evaluation results are shown in Table 1.

[Example 2]
As an ion conductive membrane, a perfluorosulfonic acid / PTFE copolymer (trade name “Nafion ^™ ”, manufactured by DuPont) having a thickness of about 200 microns was prepared (proton type) (2 cm × 5 cm). This Nafion membrane was heated in 500 mL of 5M nitric acid aqueous solution at 80 ° C. to 100 ° C. for 30 minutes and washed thoroughly with ion-exchanged water. Next, it was immersed in 500 mL of ion exchange water and boiled for about 30 minutes. Furthermore, it was immersed for about 1 hour in 500 mL of about 0.2M lithium hydroxide solution. The membrane exchanged with lithium ions is rinsed well with ion exchange water and washed. Dry in an oven set at 120 ° C for about 10 hours. The film thus obtained was immersed in ionic liquid 1-ethyl-3-methylimidazolium trifluoromethanesulfonate for about 10 hours. In this way, an ion conductive membrane (Nafion) membrane used for the composite material was obtained.

On the other hand, about 60 g / m ² of polyester fabric (taffeta) is gold-plated by a known method to obtain a conductive fabric having a surface resistance of 0.1 Ω / □ (thickness: 90 μm, average stretch; %, 10% in the bias direction, and a difference in stretchability in the bias direction; about 0%). Two pieces of this conductive fabric (2 cm × 5 cm) are cut out in the bias direction, immersed in a lower alcohol solution in which Nafion is dissolved, and then the previously washed Nafion membrane is quickly sandwiched between the two nonwoven fabrics. It is.

  The obtained sandwich is quickly covered with two polyester (PET) films of about 6 cm × 10 cm from both sides, and set in a hot press set at a temperature of 90 ° C. Apply a pressure of about 0.5 tons at the start. After 30 minutes, a composite material in which an ion conductive membrane and a conductive fabric (nonwoven fabric) were laminated was obtained. It was confirmed that the non-woven fabric of the obtained composite material and the Nafion membrane were in close contact, and that the membrane was deformed by a DC voltage of about 1 to 5V. Moreover, as a result of evaluating the tensile strength and the bending resistance of the composite material, both were excellent. The evaluation results are shown in Table 1.

[Example 3]
About 60 g / m ² of polyester fabric (taffeta) is provided with a copper plating film by a known method, and further, nickel plating is applied on the copper film to form a conductive cloth having a surface resistance value of 0.05Ω / □ (thickness: 90 μm, Average stretch degree: about 0% for both vertical and horizontal, 10% in the bias direction, difference in stretchability in the bias direction; about 0%). A composite material was produced and evaluated according to Example 1 except that the obtained conductive cloth of copper / nickel plating was used. It confirmed that it deform | transformed with the DC voltage of about 1-5V. Moreover, as a result of evaluating the tensile strength and the bending resistance of the composite material exchanged with lithium ions, both were excellent. The evaluation results are shown in Table 1.

[Example 4]
The film thickness of the ion conductive film is changed from 200 microns to 800 microns, and the conductive fabric is knitted from a woven fabric (gold plating, surface resistance value: 0.1 Ω / □, thickness: 90 μm, average elasticity: 10% in all directions, A composite material was produced according to Example 1 except that the difference in stretchability was changed to 0%), and the results were excellent as a result of evaluating deformation and bending resistance with voltage. The evaluation results are shown in Table 1.

[Example 5]
The shape of each of the ion conductive membrane, the conductive fabric, and the composite material is about 5 cm × 5 cm, and the conductive fabric is a tricot that extends little in one direction of the square and extends well in the other direction perpendicular thereto. Other than using conductive fabric (gold plating, surface resistance value: 0.1 Ω / □, thickness: 90 μm, average stretch degree: 0% in the vertical direction, 5% in the horizontal direction, difference in stretchability: 5%) Manufactured the composite material according to Example 1, and evaluated it with the evaluation sample cut to 15x15 mm. It confirmed that it deform | transformed in the direction excellent in the elasticity of the electrically conductive cloth with the voltage of about 1-5V. It was also excellent in flexibility. The evaluation results are shown in Table 1.

[Example 6]
As an electrode to be joined to one side of the ion conductive membrane, a circular knitted conductive fabric having an elongation (average stretch) of 10% or more in all directions and a woven conductive fabric having almost no elongation on the other side are used. It was. Except for this, composite materials were produced and evaluated according to Example 1. As a result, all of deformation, bending and strength when voltage was applied were excellent. The evaluation results are shown in Table 1.

[Comparative Example 1]
A conductive cloth was not used for electrode formation, and a gold plating film having a thickness of 3 microns was directly formed on the ion conductive film by an electroless plating method. It took about 50 hours to form the electrode by the plating method. A composite material was prepared in accordance with Example 1 except for the electrodes, and the deformation, flex resistance, and tensile strength at 1 to 5 V were evaluated. As a result, compared with Example 1, it was hard to deform | transform and was inferior to tensile strength and bending resistance. The evaluation results are shown in Table 1.

[Comparative Example 2]
A conductive fabric was not used for electrode formation, and a 3 micron gold plating film was directly formed on an ion conductive film of about 800 microns by an electroless plating method. It took about 50 hours to form the electrode by the plating method. A composite material was prepared in accordance with Example 1 except for the electrodes, and the deformation, flex resistance, and tensile strength at 1 to 5 V were evaluated. As a result, compared with Example 3, it hardly deformed at a voltage of 1 to 5 V, and was inferior in tensile strength and flex resistance. The evaluation results are shown in Table 1.

[Comparative Example 3]
A composite material was produced and evaluated according to Example 5 except that the electrode was directly formed on the ion conductive membrane. As a result, the deformation was only slightly deformed at the four corners of the square. Bending resistance and tensile strength were also inferior. The evaluation results are shown in Table 1.

  Since the composite material of the present invention uses a conductive fabric excellent in flexibility, stretchability, and flexibility as electrodes to be bonded to both surfaces of the ion conductive membrane, the deformation amount when applying a potential difference is large and quick response Excellent in controllability and deformation control. In addition, it has a high degree of freedom in shape, is excellent in practically necessary strength and durability, and is economical. Therefore, the composite material of the present invention can be applied as an actuator element to various uses such as medical equipment, industrial robots, and micromachines. For example, it can be used as an artificial muscle for a micro robot operating in water, and can also be applied to the power of a medical instrument used in a living body.

In one Example of the composite material of this invention, it is a sectional side view in the state which does not apply a potential difference. In one Example of the composite material of this invention, it is a sectional side view in the state which applied the electric potential difference. It is the schematic which shows an example of the manufacturing method of the composite material of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ion conductive film 2 Conductive fabric 2 'Conductive fabric 3 Positive ion 4 Cover or supporter

Claims (8)

A composite material comprising an ion conductive film and electrodes joined to both surfaces of the ion conductive film, and causing the ion conductive film to be deformed by applying a potential difference to the electrode, wherein the electrode is composed of a conductive cloth. A composite material characterized by that. The composite material according to claim 1, wherein the ion conductive membrane is an ion exchange membrane or a membrane impregnated with an ionic liquid. 3. The composite material according to claim 2, wherein the ion exchange membrane or the membrane impregnated with an ionic liquid is made of a fluororesin polymer. The composite material according to any one of claims 1 to 3, wherein the conductive fabric is a composite of a fabric and a metal by a plating method or metal complex injection. The composite material according to any one of claims 1 to 4, wherein an electrode bonded to at least one surface of the ion conductive film is made of a conductive cloth having stretchability. The composite material according to claim 1, wherein the conductive fabric has a difference in stretchability between two orthogonal axes. The composite material according to claim 6, wherein the difference in stretchability is 2% or more. 8. The conductive fabric according to claim 5, wherein the conductive fabric is joined to the ion conductive membrane so as to be stretchable in a direction in which the ion conductive membrane is deformed when a potential difference is applied to the electrodes. The composite material according to any one of the above.

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